Field of the Invention
The present invention relates to linkable light emitting diode (LED) lighting fixtures and systems, and in particular to linkable LED lighting fixtures and systems, and linkable strip lighting fixtures and systems.
Description of the Prior Art
There are many lighting fixtures which are used for a variety of purposes including workshops, offices, factories, residences, schools and the like, which until fairly recently the market for such fixtures was largely filled with incandescent bulbs and fluorescent lights. A big problem with incandescent bulbs is that they convert most of their energy into heat as opposed to light, thus wasting electricity and generating unnecessary warmth. Fluorescent lighting generally involves ionizing a gas such as argon contained within a sealed tube. The electrically-excited gas produces light emission as the gas returns to its normal energy level. Although fluorescent lighting is widely used, it does have serious shortcomings. Fluorescent lighting is rather complex, and repairs can be costly both with respect to replacing ballasts and other components which may have to be replaced from time to time, and with respect to the high voltage that is needed for fluorescent lighting. The high voltage makes necessary added electrical insulation, and the requirement for safety precautions.
Compact fluorescent light bulbs have also become popular. Compact fluorescent lights, or CFLs convert most of their energy into light rather than heat. CFLs last longer than incandescent lights and are designed to fit into existing incandescent lighting fixtures. CFLs use about ¼ of the electricity required for incandescent bulbs while producing a comparable amount of light. While CFLs do not flicker when used for an extended period of time, they do have flickering problems if switched on and off frequently. Furthermore, the switching process takes more time than is desirable so that CFLs take a longer time to light before they become fully lit. Furthermore, CFLs require optimum temperatures to work and are known to function in less than their rated capacity when switched on in lower temperatures.
LEDs are becoming more and more popular. LEDs require lower power consumption than do CFLs.
A single LED is very small, but a combination of bunches of LEDs create powerful lights which can withstand more extreme conditions than ordinary bulbs. LEDs use about 1/50 of the energy of the standard incandescent bulbs, and last ten times longer than CFL alternatives. Indeed, LED bulbs can last up to fifteen years without needing to be changed. LEDs furthermore produce smaller amounts of heat than do CFLs, and the heat which is produced by LEDs is usually past back to a heat sink making them cool to the touch. With respect to energy efficiency, whereas a CFL uses less than fifteen watts and costs about $75.00 per year, an LED bulb of similar output would draw less than eight watts of power with an annual cost of $30.00 and last 50,000 hours or more.
There is also a disposal problem with CFL bulbs. CFL bulbs contain mercury which can evaporate and cause air and water pollution. Furthermore, mercury is a neurotoxin that can have a harmful effect on humans, particularly infants. Thus, disposal of CFLs and regular fluorescent bulbs can be a problem since they may break and release the mercury. They can thus be a problem for landfills and waste management workers, in addition to the environmental problems noted above.
The danger of CFLs is severe. The Environmental Protection Agency (EPA) has approved CFL recycling sites. Furthermore, the EPA recommends that in case a CFL breaks in a home, all members and pets are recommended to leave the room. The room has to be aired out for 10-15 minutes, the central forced air should be shut off, and the shards should be collected with stiff paper, tape or a damp paper towel, and then put in a glass jar with a metal lid or a sealable plastic bag and then taken to a recycling site. On the other hand, LED bulbs do not come with a mercury hazard, and most of them are recyclable.
There are other comparisons which indicate that LED bulbs are preferable over CFLs. CFLs require time after actuation in order for them to warm up to full capacity, whereas LED bulbs do not require any length of time to become active. CFLs may not work in temperatures that are less than −10° F. or greater than 100° F. whereas LED bulbs are not temperature sensitive. CFLs are not dimmable, whereas LED bulbs are dimmable. Although LED bulbs cost more than CFLs, the total cost of LED bulbs is less than the cost of CFLs during the life of the LEDs.
Thus, LED bulbs and LED lighting fixtures have been becoming more and more popular over time. In many instances, a single LED lighting fixture may be sufficient for such uses as in workshops. However, oftentimes a number of LED lighting fixtures would be desirable. One could install a series of independent LED lighting fixtures which need to be turned on and off as needed. This could be expensive, and could require a number of receptacles provided along the area which is to be illuminated. This concept has been addressed previously, but there are various shortcomings. Referring to U.S. Pat. No. 7,192,160, a set of fluorescent and/or LED light sources is shown having a control box for switching between two light sources is discussed. A series of lights can be electrically linked in series, and each light is provided with a control box so that the individual lights can be individually operated. This can be used in military barracks, wherein each soldier would be able to control his own light. However, this embodiment requires a series of control boxes, making the system expensive. Alternatively, the string of lights can have one control box in which all of the lights are operated in series. The first light in the series of lights is the master and the remaining lights that are connected are slave lights. Thus, all of the lights must be operated together, rather than one at a time.
Another light tube system is disclosed in U.S. Pat. No. 7,513,640. Light tube system can have a number of light tube units which are connected together by cables. The cables have connector pins which extend in a direction perpendicular to the longitudinal direction of the light tubes, making it awkward to connect them together. There is no indication in the '640 patent as to where the on-off switch is located. The light tubes discussed in this patent appear to be fluorescent tubes, and thus have all of the shortcomings of fluorescent bulbs discussed above.
In U.S. Pat. No. 9,004,716, a set of LED tubes are connected together by adaptors so that the tubes extend in a collinear direction. The adaptors include an adaptor main body and rotational fittings. A shortcoming of the disclosure of this patent is that the LED tubes must be fixed in a certain position, and no variation of the position is possible. There is also no device for hanging the assemblies at their opposite ends.
In U.S. Publication No. 2012/0188756, another master/slave LED work light is disclosed. The work light has a power cord that extends entirely through the work light for connecting the work lights together. A master/slave LED work light lighting network and remotely controlled lighting network is disclosed. There is a master light and a number of slave lights that are controlled by the master light. This means that the individual lights cannot be controlled separately. This arrangement has a serious shortcoming if the lighting apparatus is to be used in an area where the lights in the string need to be turned on or off depending on the current situation.
Another type of LED light engines is referred to as strip lights. Strip lights are conventionally flexible strips on which LEDs are mounted, and the flexible strips usually come with an adhesive backing so that they can be attached to walls, fixtures and the like. LED strip lights are sometimes referred to as LED tapes or ribbon lights. Strip lights can be water resistant, and if so they can be used for both indoor and outdoor lighting. Strip lighting is often used for colors other than white. All LED strip lights require a driver and generally operate on a 12 or 24 volt direct current from the driver.
However, strip lighting is often used for such areas as workbench lighting and also for office lighting and artistic lighting. When used with a workbench, strip lighting can be used to eliminate shadows that would often occur with behind the shoulder lighting. LED strip lighting can also be used to eliminate shadows. LED strip lighting also finds use with desks such as with use with a monitor, preferably not being used in a dark room or with strong lights which can cause screen glare. The use of an LED strip light behind the monitor can create a gradual shift between the brightness of the monitor and the light in the rest of the room to reduce eye strain. LED strip lighting can be used in artists' studios to avoid harsh or bright lights which are close to natural light.
U.S. Pat. No. 6,283,612 discloses an LED light strip and incorporates an array of solid state LEDs inside of a transparent or translucent tube. A single power supply can energize up to 350 LEDs in the white configuration. The light strip disclosed in this patent finds particular use in lighting candy displays in stores and markets. The strip light disclosed in this patent has a solidly mounted circuit board held in the tube firmly so that it is vibration resistant. A pair of end caps is located at opposite ends of the tube to plug each end, and a wire penetrates the cap and is potted or sealed so as to make the light waterproof. The light strip includes an electrical cable connected to busses on a single end or on both ends of the light, and a male or female connector can be incorporated. One embodiment of the LED light strip disclosed in the latter patent is said to enable the attachment of a number of light strips together by means of an electric cable and connector for attaching the busses together to prepare for a parallel connection between light strips so that they can be connected together limited only by the ability of the power supply. The individual LED light strips cannot operate separately and must therefore be used on and off together. There is no indication that the light strip set forth in the foregoing patent for anything other than illuminating displays and not in various work areas.